1. Which two commands are required to enable multicast on a router, knowing that the receivers only support IGMPv2? (Choose two)
A. ip pim rp-address
B. ip pim ssm
C. ip pim sparse-mode
D. ip pim passive
Answer: A,C
Explanation: http://www.cisco.com/en/US/docs/ios/12_2/ip/configuration/guide/1cfmulti.html#wp1000948
2. Apart from interdomain multicast routing, what else is MSDP used for?
A. Source Specific Multicast and IGMPv2
B. Announcing multicast sources to BGP speakers
C. Anycast RP
D. Intradomain multicast routing
Answer: C
Explanation: http://www.cisco.com/en/US/docs/ios/solutions_docs/ip_multicast/White_papers/anycast.html
3. Which IGMPv2 message contains a non-zero “Max Response Time”?
A. Membership Query
B. Membership Report
C. Membership Delay
D. Backward Compatible IGMPv1 Report Message
Answer: A
Explanation: “The Max Response Time field is meaningful only in Membership Query messages” from the RFC https://tools.ietf.org/html/rfc2236
4. See exhibit above. Which IGMPv2 message is displayed in the output of the packet capture?
A. General Query
B. Membership Report
C. Membership Query
D. Membership Delay
Answer: B
Explanation: N/A. Best guess is the image shows Options set to have every router inspect.
5. What is Phantom RP used for?
A. it is used for load balancing in bidirectional PIM
B. it is used for redundancy in bidirectional PIM
C. it is used for redundancy in PIM-SM
D. it is used for load balancing in PIM-SM
Answer: B
Explanation: http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6552/ps6592/prod_white_paper0900aecd80310db2.pdf
6. In PIM-SM what control plane signaling must a multicast source perform before it begins to send multicast traffic to a group?
A. The source must send a PIM Register message to the rendezvous point (RP).
B. The source must first join the multicast group using IGMP before sending.
C. The source must perform a Request to Send (RTS) and Clear to Send (CTS) handshake with the PIM designated router (DR).
D. No control plane signaling needs to be performed; the source can simply begin sending on the local subnet.
Answer: D
Explanation: http://www.ietf.org/rfc/rfc2362.txt
7. Which of these statements about PIM join messages in classic PIM-SM is correct?
A. PIM join messages are sent every 60 seconds to refresh the upstream router’s mroute state for the multicast tree.
B. Routers send a PIM join acknowledgement in response to each PIM join message received from a downstream router.
C. PIM join messages are only sent when the multicast distribution tree is first being established.
D. PIM join messages are sent every three minutes to refresh the upstream router’s mroute state for the multicast tree.
Answer: A
Explanation: http://www.ietf.org/rfc/rfc2362.txt
8. The “ip pim autorp listener” command is used to do which of these?
A. enable a Cisco router to “passively” listen to Auto-RP packets without the router actively sending or forwarding any of the packets
B. allow Auto-RP packets in groups 224.0.1.39 and 224.0.1.40 to be flooded in dense mode out interfaces configured with the ip pim sparse-mode command
C. enable the use of Auto-RP on a router
D. configure the router as an Auto-RP mapping agent
Answer: B
Explanation: http://www.cisco.com/en/US/docs/ios/12_2/ipmulti/command/reference/1rfmult2.html#wp1090395
9. In order to configure two routers as anycast RPs, which of these requirements, at a minimum, must be satisfied?
A. Multicast Source Discovery Protocol mesh-groups must be configured between the two anycast RPs.
B. The RPs must be within the same IGP domain.
C. Multicast Source Discovery Protocol must be configured between the two anycast RPs.
D. The two anycast RPs must be IBGP peers.
Answer: C
Explanation: http://www.cisco.com/en/US/docs/ios/solutions_docs/ip_multicast/White_papers/anycast.html
10. Which two of these statements correctly describe classic PIM-SM? (Choose two.)
A. The lOS default is for a last-hop router to trigger a switch to the shortest path tree as soon as a new source is detected on the shared tree
B. The lOS default is for every one of the routers on the shared tree to trigger a switch to the shortest path tree as soon as a new source is detected on the shared tree.
C. The default behavior of switching to the shortest path tree as soon as a new source is detected on the shared tree can be disabled by setting the value in the ip pirn spt-threshold command to infinity.
D. The default behavior of switching to the shortest path tree as soon as a new source is detected on the shared tree can be disabled by setting the value in the ip pim spt-threshold command to “zero.”
Answer: A,C
Explanation: http://www.cisco.com/en/US/tech/tk828/tech_brief09186a00800a4415.html#wp17813
11. Refer to the exhibit above. Router E learned about the PIM RP (designated as 7.7.7.7) from four different sources. Routers A and D advertised the 7.0.0.0 network via EIGRP. Routers B and C advertised the 7.0.0.0 network via OSPF. Considering that all four Ethernet interfaces on router E could potentially lead back to the PIM-RP, when router E receives the first multicast packet down the shared tree, which incoming interface will be used to successfully pass the RPF check?
A. E0
B. E1
C. E2
D. E3
E. None of these interfaces will be used to successfully pass the RPF check.
F. All of these interfaces would successfully pass the RPF check.
Answer: A
Explanation: By default, if ECMP paths are available, the RPF for multicast traffic will be based on the highest IP address. See URL
http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6552/ps6592/whitepaper_c11-474791.html
Switch#show mac-address-table multicast
12. Refer to the exhibit above. From the MAC addresses shown in the command output, to which two ports is the multicast stream 225.230.57.199 being forwarded on this switch? (Choose two.)
A. Fa6/28
B. Fa7/20
C. Gi3/7
D. Fa4/2
E. Fa4/14
F. Fa4/38
G. Fa6/28
H. Fa5/7
Answer: C,E
Explanation: Do the math.
http://routemyworld.com/2009/03/04/ip-multicast-to-mac-address-mapping/
13. See exhibit. Two ISPs have decided to use MSDP and configured routers X and Y (both are PIM RPs) as MSDP peers. In the domain of ISP B, PC A has sent an IGMP membership report for the group 224.1.1.1 and PC B has sent an IGMP membership report for the group 224.5.5.5. Assuming that the MSDP peering relationship between routers X and Y is functional, and given the partial configuration output shown from router X, which two of these statements are true? Choose two.
A. Router X will contain an entry for 224.1.1.1 in its SA cache and will also have an installed (S,G) entry for this in its mroute table.
B. Router X will not contain an entry for 224.1.1.1 in its SA cache but will have an installed (*,G) entry for this in its mroute table.
C. Router X will not contain an entry for 224.5.5.5 in its SA cache but will have an installed (S,G) entry for this in its mroute table.
D. Router X will not contain an entry for 224.5.5.5 in its SA cache but will have an installed (*,G) entry for this in its mroute table.
E. Router X will have no entries for 224.5.5.5 in neither its SA cache nor in its mroute table.
F. Router X will have no entries for 224.1.1.1 in neither its SA cache nor in its mroute table.
Answer: A,D
Explanation: n/a
14. Which three statements are true about Source Specific Multicast?
A. Is best suited for applications that are in the one-to-many category.
B. SSM uses shortest path trees only.
C. The use of SSM is recommended when there are many sources and it is desirable to keep the amount of mroute state in the routers in the network to a minimum
D. There are no RPs to worry about
Answer: A,B,D
15. Which statement is true of a source that wants to transmit multicast traffic to group 239.1.1.1?
A. Before sending traffic, it must first join multicast group 239.1.1.1 by sending an IGMPv2 membership report to the default router on the local subnet.
B. It must send an IGMPv2 Request to Send packet and then wait for an IGMPv2 Clear to Send packet from the IGMPv2 querier router on the local subnet
C. It may begin transmitting multicast traffic to the group only when there is no other host transmitting to the group on the local subnet.
D. It may transmit multicast traffic to the group at any time.
Answer: D
Explanation:
16. We have IPv6 multicast configured between R5 and R6, which three statements are true based on the partial command output shown? (Choose three)
A. I R6 has joined one multicast group, and it expires in 46 seconds.
B. The rendezvous point address is 2001:DB8:5::5.
C. The multicast group address is FE80::216.
D. R6 has joined two multicast groups, and it expires in 7 seconds.
E. The multicast entry is operating in sparse mode.
F. The multicast groups are FF04::10 and FF04::30.
Answer: B,E,F
Explanation: http://www.cisco.com/en/US/docs/ios/ipv6/command/reference/ipv6_14.html#wp2378397
17. We have IPv6 multicast configured between R5 and R6. Which two statements are true based on the partial command output shown? (Choose two.)
A. R6 has joined the multicast group, and it expires in 46 seconds
B. The rendezvous point address is FE80::21 6:47FF:FEBB:FFO.
C. The multicast group address is FF04::1 0.
D. The multicast entry is operating in dense mode.
E. The multicast route has been pruned.
Answer: C,E
Explanation: http://www.cisco.com/en/US/docs/ios/ipv6/command/reference/ipv6_14.html#wp2378397
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